Hard metal alloy



' place-either by sinterlng or by melting.

assess as, we

'llAL on Julius Eolzger, Bach, near Munich, Ger- Bolil gnor, by eManta-to Gehr- & 80., Ahtieng chait, r, Ger

No a. Application May d, 1931, Serial No.

The hard metals according to the present invention difier from thealloys hitherto known by their not being based on tungsten-carbides.Their main .efiective ingredients are one or sev- 5 eral carbides oi theelements zirconium, titanium,

thorium, cerium.

Whereas it has been proposed before now to add titaniumandthorium-carbide to hard metal alloys, the proportion added-has alwaysbeen a small one and the basis has always been tungsten-carbide.

The present invention on the contrary has made it possible to obtain analloy with the elements carbon, zirconium. titanium, thorium, cerium asthe main effective constituent (and in particular titanium carbide), ofwhich formed pieces voi any kind or shape can be made for hard metaltools and implements, which distin: guish themselves by their greathardness, and

"their extraordinary sharpness and toughness.

An important improvement has been achieved by alloying carbides of thetitanium group consisting of titanium, zirconium, thorium and ceriumwith the elements of the chromium group (chromium, molybdenum, tungsten)and ele-. ments of the iron group (iron, cobalt, nickel,

manganese) or with elements from both groups. The ingredients ofelements of the titanium group must amount to at least 20% and theingredients of elements of the iron and/or chromium group must amount toat least 8%. The binding of the. carbides of the titanium group with theelements of their-on and/or chromium group canaccording to thisinventlontake The sintering temperature for instancev lies at about1400-1700" C. and the melting temperature above it, though no definitelimits can be drawn, as these depend on the kind and proportion of thecomponents. As for the molten alloys it is true that a process forobtaining molten bodies of titamum-carbide with low melting auxiliarymetals has become known, but only if the proportion of titanium-carbidewas not below 60%, serviceable tools could be obtained by this process.I, on the contrary have found, that a specially good product isobtained'by using molten alloys as'described in the examples mentionedhereafter. The combination of the titanium group-carbides with theelements of the iron and/or chromium group can also be carried out insuch a manner that the binding mediums are made up separately in theform of an alloy of the iron or chromium group respectively, that theyare then united with the pressed carbide body and brought to Germany May'5, 1930.

dlfiuse by heat treatment. It is true, that a process of imbibingcarbides with low melting metals is known, but-this is based onthecapillary efiect of sintered carbides. The carbides of the titaniumgroup do not show the peculiarity of the capillary suction forces. Tounite these carbides with binding mediums the latter have to be heatedabout 800 to 300 above the melting point. Only owing to this overheatingthe melt begins to act on the carbide body and to penetrate therein.After the absorption of the melt by the carbide body it is necessary tofurther increase the temperature 50 to 100 C. for a short period inorder to obtain a uniformly penetrated body.

Among others the following are examples of hard metals for cutting toolsand other implements accor to the present invention:

with apart by weight of at least 25%. This is due to the fact that theefiect of these elements does not depend on the part by weight but onthe part by volume which is at leastequal to the part by volume of anyother constituent of the alloy in a powdery form or state, 1

Molten hard met'aifalloys of tungsten or tungstem-carbide as main-'constitue t have hitherto become mown to which titani and zirconium upto 20 may be added. However, siutered hard metal alloys were notknownwhich consist of at least one \of the elements titanium or zirconium andslsocarbon as nl. constituent with at least one binding metal from themetals of the chromium or the iron groups. It has proved very ad'-- toknown hard metals for working metals, glass, coal and rock.

The binding of the carbides and other constitsolid state. When sinteringthe powdery mixture,

1 a certain reciprocal action of the carbon takes place between titaniumand zirconium carbide on the one hand and the elements of the chromiumgroup on the other hand so that in addition to, for instance, titaniumcarbide, elementary titanium may be present and in addition to tungsten,or chromium. tungsten carbide and chromium carbide may be present.

What I claim is:

- 1. Sintered hard metal alloy for working tools, consisting of 35 to45% T1, to-% Ni, 5 to 10% Cr., 10 to 20% W, and 6 to 10% C, the Tibeingin carbide iorm.

2. Sintered hard metal alloy for working tools. consisting of 30 to Ti,15 to 25% Co, 15 to 25% Cr, 15 to 25% W and 7 to 10% C, the Tibeing incarbide form. v

3. A sintered hard metal alloy for working tools, consisting of between20 and of titanium carbide, between 15 and 01' the elements chromium andtungsten taken together, there being at least 5% or each of the said twoelements, and the balance consisting of a substantial amount of the irongroup; said alloy containing between 6 and 10% carbon.

, JULIUS HOLZBERGER.

